Abstract

The muscle relaxant mivacurium (MIV), is made up of 3 isomers: trans-trans (tt; 55%), cis-trans (ct; 36%), and cis-cis (cc; 6%). Plasma cholinesterase (ChE) converts these compounds into 2 alcohol and 2 acid isomers. Hypothermic cardiopulmonary bypass (CPB) may be expected to impair these metabolic pathways by both reducing ChE activity and a direct effect of hypothermia. The present study was designed to analyse the disposition of the MIV isomers before, during and after CPB in the clinical setting.